Optical Calcite (Iceland Spar) – Maharashtra, India – 1.49 lbs

A striking Optical Calcite (Iceland Spar) specimen from Maharashtra, India, featuring exceptionally transparent calcite crystals accompanied by attractive cream-colored stilbite on natural volcanic matrix.

This specimen displays the remarkable clarity for which optical calcite is famous. The translucent calcite crystals exhibit glassy faces and excellent internal transparency, while the accompanying stilbite adds soft pearly contrast and architectural balance. Together, the minerals create a beautiful association that showcases two classic species from the famous Deccan Traps.

Optical calcite is renowned for its extraordinary optical properties, particularly its ability to produce double refraction (birefringence). When viewed through clear crystals, objects beneath appear doubled—a phenomenon that has fascinated scientists and collectors for centuries and helped advance the study of crystallography and optics.

At approximately 1.49 pounds and measuring roughly 4 × 3 × 3 inches, this specimen offers excellent cabinet presence while remaining an ideal display size. Its combination of transparent calcite, elegant stilbite associations, and classic Maharashtra provenance makes it an outstanding addition to any mineral collection.

Specifications

Mineral: Optical Calcite (Iceland Spar) with Stilbite

Locality: Maharashtra, India

Weight: 1.49 lbs (approximately 676 grams)

Dimensions: Approximately 4 × 3 × 3 inches

Crystal Habit: Transparent rhombohedral calcite with fan-shaped stilbite

Color: Colorless to white with creamy white stilbite

Luster: Vitreous to pearly

Matrix: Natural volcanic basalt matrix

Condition: Natural collector specimen

Display: Cabinet specimen with transparent optical crystals

Exact specimen shown

About Optical Calcite (Iceland Spar)

Optical calcite, historically known as Iceland Spar, is one of the most famous varieties of calcite because of its exceptional transparency and remarkable optical behavior. Large transparent crystals display strong double refraction, causing objects viewed through the crystal to appear doubled due to the mineral's birefringence.

Although the name originated from famous deposits in Iceland, transparent optical calcite is also found in select localities worldwide, including the zeolite-bearing basalt cavities of Maharashtra, India. Here, hydrothermal mineral-rich fluids deposited calcite alongside zeolite minerals such as stilbite, apophyllite, and heulandite within cavities formed by ancient volcanic eruptions.

Specimens combining transparent optical calcite with attractive zeolite associations are especially desirable because they unite scientific significance with exceptional natural beauty.

Collector Notes

This specimen features:

• transparent optical calcite crystals
• classic Iceland spar variety
• associated pearly stilbite crystals
• excellent natural transparency
• classic Maharashtra zeolite locality
• attractive multi-mineral association
• strong vitreous crystal luster
• substantial 1.49-pound cabinet size
• natural volcanic basalt matrix
• excellent three-dimensional display
• scientifically significant optical mineral

Perfect for collectors of optical calcite, Iceland spar, calcite specimens, Indian zeolites, stilbite associations, Maharashtra minerals, transparent crystals, cabinet specimens, educational mineral displays, and museum-quality collector minerals.

Professionally packaged and shipped from Colorado.

You will receive the exact specimen shown.

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